The CLAMP Control Loop Participant protocol is an asynchronous protocol that is used by the CLAMP runtime to coordinate life cycle management of Control Loop instances. The protocol supports the functions described in the sections below.

Protocol Dialogues

The protocol supports the dialogues described below.

Participant Registration and De-Registration

Registration when a participant comes up and update of participant with control loop type information and common parameter values for its control loop types.

De-registration is executed as a participant goes down.

Control Loop Commissioning and Decommissioning

When a control loop is commissioned, the portion of the Control Loop Type Definition and Common Property values for the participants of each participant type mentioned in the Control Loop Definition are sent to the participants.

When a control loop is de-commissioned, the portion of the Control Loop Type Definition and Common Property values for the participants of each participant type mentioned in the Control Loop Definition are deleted participants.

Control Loop Update

Control Loop Update handles creation, change, and deletion of control loops on participants. Change of control loops uses a semantic versioning approach and follow the semantics described on the page TOSCA Defined Control Loop: Architecture and Design.

The handling of a ControlLoopUpdate message in each participant is as shown below.

Control Loop State Change

This dialogue is used to change the state of Control Loops and their Control Loop Elements. the CLAMP Runtime sends a Control Loop State Change message on the control loop to all participants. Participants that have Control Loop Elements in that Control Loop attempt an update on the state of the control loop elements they have for that control loop, and report the result back.

The handling of a ControlLoopStateChange message in each participant is as shown below.

Control Loop Monitoring and Reporting

This dialogue is used as a heartbeat mechanism for participants, to monitor the status of Control Loop Elements, and to gather statistics on control loops. The ParticipantStatus message is sent periodically by each participant. The reporting interval for sending the message is configurable.

Messages

The CLAMP Control Loop Participant Protocol uses the following messages. The descriptions below give an overview of each message. For the precise definition of the messages, see the CLAMP code at: https://github.com/onap/policy-clamp/tree/master/models/src/main/java/org/onap/policy/clamp/controlloop/models/messages/dmaap/participant.

Participant Registration

Participant Registration Ack

Participant Update

Participant Update Ack

Participant Deregistration

Participant Deregistration Ack

Control Loop Update

Control Loop Update Ack

Control Loop State Change

Participant Status